HOOD SCOOP

a scoop I'm working on, trying to get a look somewhat akin to a healy but more aggressive, plan to blend in the sides, not sure how I'll deal with the front. any ideas

another

Why the scoop?

I think if you can get the sides to roll to the hood, Jay, you'll be onto something. With rolled edges, it'll "flow" with the car's lines. Straight down, it'll always look like an add-on. I can see the "Healy" in that.

Try this as a comparison.

Also where does the air from the vent go to. Is it directed behind the radiator or is it within the bonnet structure and directly to the carbs.
Is it a true vent or fashion.

Do you need a scoop to clear the motor? Otherwise I'd save myself a lot of trouble and leave it alone. It is really hard to do what you are attempting and have it come off looking professional.

If you DO need a shallow bump, consider buying a fibreglass MGC bonnet....

It is a lot less work to make the motor fit right than to make a scoop look right.

For some people a scoop on a car with a retrofitted powerplant radiates a lower quality job (i.e. the person couldnt get it to fit inside, so they had to chop a hle in the hood). For others it looks cool because it says there's a motor in the car so big it doesnt fit under the hood.
IMHO, on a new car, it looks like marketing guys wanted you to think 'huge motor'; on an old car (no matter how fancy the bodywork) it looks like a kludge.

I like it. I would. I think he's on the right track, and am anxious to see how it finishes. It starts way back near the cowl, much like the MGC hood.

Everyone's going to have opinions on everything. I like the scoop and commend Jay for trying something different. It's his car, he can do what he likes. I had the scoop installed on my car primarily for the increase in airflow. IMO, it compliments the car and is functional.

To each his own.

I think we need some sort of forum shorthand. Every time anyone posts something that doesn't meet with universal approval, half the responses are taken up with apologies by some members for other members' posts saying it wasn't their cuppa tea.

I am reminded of the Seinfeld "Not that there is anything wrong with that".

Anyone that comes up with a shorthand for that will save endless pages of postings on the forum! Maybe we could have it incorporated as a smiley face symbol of some sort?

In the mean time, anyone that posts saying "What do you think of this" has to be ready to take the brickbats along with the posies. Maybe we need that in a FAQ? :D

To the OP - I wonder if you could take a fibreglass MGC bonnet and sinply cut into the end of the 'hump' to open it up? Less is often more when it comes to intake vents.

Here is one on a Jensen FF. Easy to tell that the same factory built the Healey pictured above - just a small air opening as a styling accent.

great idea Jay !!!!! Keep us posted.

Could be really cool, keep at it! How about getting a healey hood moulding and build off of that? Here's one: http://cgi.ebay.com/ebaymotors/Austin-Healey-Grill-Air-Intake-on-Bonnet_W0QQitemZ2485612819QQcmdZViewItemQQptZMotors_Car_Truck_Parts_Accessories?hash=item94277113

There was an MGC offered for sale recently on the UK Ebay. It had the front of the power bulge of the bonnet cut out. Looked abysmal.

Sorry.

The man asked for opinions /impressions, that's what was offered. If you are not interested skip that page

What happens when a negative touches the positive SPARKS !!!! LOL

just got home and am catching up on the posts relative to the hood scoop.

postive or negative, opinions are opinions and when you ask for them you'll inevitabley get both. it would be a shame to be so thin skinned as to not listen to them all. there is a lot of good thinking going on here. thanks all!!

Simon, I think you are right about blending into the hood (sides tapering from the top of the scoop outwards to the hood) would look better vs. straight down looking "add-on".

David, everything I'm doing to the car is functionality, the degree of effectivity may be debateable and/or questionable, afterall I have a missus to contend with. good picture of the healy.

the engine fits well within the bay, no bumps, lumps and humps needed for clearance. I would like to get a bit of positive pressure in the intake system when at speed (2-4 inch pressure) and cool air is the justification, I like the looks the modivation.

Bill "brickbats with the posies" as in flowers? thats a good one. OP? other people. I had a CGT and put black tape on the forward part of the raised center, basically from the chrome strip to the original hood line to similate an opening, wasn't impressed at all, it seemed out of place. I wanted something in two planes with different curvatures, raising the center section like I have seems to satisfy that "visual appeal" that I didn't "see" with the "C" hood

attached is a "rough draft" pic of the planned workings beneath the hood.

planned layout, haven't worked out all the detail, it will happen. any suggestions as to how to make the front appealing? along the lines of a closeout/trim, maybe roll the front edge back? something that would dress-up the opening?

Having never done anything like this it is all easy to me--maybe you could curve the scoop to match the curve of the hood like the Healey's. I like the Healey's hood and like the direction you're going. I agree with others, to pull it off will be the trick--to make it looks like it belongs. Good luck.

I like how the healey and jensen scoops mimick the grill lines (even the vertical bars on the healey) - not that I ever seem to take my own advice B)

I like it Jay. Like a few others, I think it'll look best if you can roll the corners rather than have sharp bends. For the front, consider either simply rolling the ends back in to give it a finished edge. Or, maybe mimic the grille -- that'd be tough with the grill you have, but consider, as an example, the chrome surround but replace the teeth with stainless wire like the upper right in this pic... you could use a heavier gauge on the grille & a moderately lighter gauge on the scoop...

I was looking at the picture oh... about two cups of coffee. I like the idea behind it. A salt flats car with a scoop, the scoop is placed way forward some time pass the hood line.
Reason is that the air current is clean, untouched by the body work, thus making it very effective.
Test have shown that a well design hood scoop can produce as much as 2-3 psi at over 100 mph. (it plays havoc with fuel mixtures) I would say that pushing the opening of the scoop forward a bit more, it could or can be more effective, now add a cool box to the intake.
As for looks it appears to me that it looks like a early Aston Martin or a Lusso Ferrari. Not bad once is finish. round edges is good, it would match the lines of the GT.

I also think that the air may be deflected by the frontal area of the hood/grill. One solution would be to extend the intake of the scoop forward or reduce the frontal area by lowering the hood line.
Those are my observations Jay, keep in mind that I had two strong cups of coffee and after two cups, well.....you know.....

Another Jensen scoop

I seriously doubt you will get 2-4" Hg pressure increase.

I used to fly a Mooney that had a "Ram" air system with the air intake on the front of the cowling. You normally flew the airplane with the intake through the filter, etc. When you got to cruise altitude you would pull a knob that allowed a direct flow from the nose inlet to the intake manifold. At about 180 mph you would see perhaps a increase in M.P. of 1" Hg. Anyway, made you feel faster.

In cars, I think most "Ram" system designs only decrease the normal systems restrictions, but do not add 'boost'. In my MGB V8, the intake air filter is located in front of the drivers side radiator shroud, more to get cool ambient air rather than warm engine compartment air.

Good luck,

Yes, 'Ram Air' isn't functional as far as boost is concerned at any legal speed, Cold air is the goal. This can often be as easily accomplished with a duct from low on the front of the car, but then that doesn't give you the look of a scoop, which people often want.

Of course you can have your cake and show it off too - just stick on whatever sort of scoop appeals to you stylistically and don't even bother to hook it up to anything, and do the cold air thing from somewhere else low down at the front of the car.

Actually a cowl induction scoop is more effective as it creates less drag,but if you want the scoop look
that's a different story.

Will the scoop upset air flow thru the radiator ??

So......many variables, opening lengh, dia of entry opening, manifold type, exhaust, valve size, carb size or FI TB etc etc.

7 psi on one engine will not measure 7 psi with and engine that has larger valves, bigger bore, big manifold etc.
Effective, yes it is effective, when done correctly and it is matched to the engine. Just an opening that feeds the carb or FI does not mean it is correct, thus making the system none effective.

SCTA cars ( flats cars), use scoops made just for force feed the engine at speed. 2 to 3 psi is not uncommon. Just a hole feeding the carb or FI will not do.

I've been reading about "scoop design" lately, here is a summary of what I found

1. most so called "ram air" intakes function more to deliver "cooler air" to the intake and do little in the way of pressurizing the intake

2. as seen on the majority of production cars these intakes are styling cues first and formost, again doing little to enhance performance.

3. provided that the actual inlet is properly placed (above the boundry layer) and sized accordingly the most difficult task will be to tune the ductwork so as to deliver non turbulent, cool"er" air the the TB

4. to make the scoop usable in all weather conditions (rainy & sunny days) a water "separator" needs to be included. sharp bends, bang plates and/or a reduction in volocity are the easiest approches.

here are my plans.
1) design a functional and appealing (to me) scoop.
2) eleminate negative pressures in the intake system
3) deliver fresh "cooler" air to the engine

4 HAVE FUN TINKERING WITH MY CAR


i have no delusions as to the difficulty of this task and my goals but I believe all are well within reach.


this is a good post, thanks all !!

[quote=TXS67BGT]

4 HAVE FUN TINKERING WITH MY CAR
quote]

And that, my friends, is what it's all about!

I once spent 4.5 months designing/testing/proofing a "decompression proof bidet", went to LA CA. had female gel dummies built, sat them on the bidet mockup and filmed the whole appratus during several cycles of rapid decompression,was that ever a hoot, the requirement was probably more of satisfying a percieved fear than any actual need.

could the scoop I'm working could be thought of in a similar light, most likely and it is equally justifiable

thanks again for the comments all

JM

Jay,

I like what you're doing. Please keep us posted. I, myself, still have to make a scoop, or more likely a cowl, for my car. Where in SA are you? I have been traveling there a lot lately, perhaps I could come by and see your car/scoop.

Brad

Jay, I'm a bit late getting in on this but here's my suggestion. If you can form the upper portion of the hood to clear your engine and then flow down to the original front portion then recess a portion on either side of the "peak" behind the MG badge. You get the intake air you want along with the clearance, but the hood doesn't look like anything was added on top, but rather that the vents were recessed into it. Sort of like Pontiac did on their G8.

Well, out of curiosity, I looked up the formula for determining “Dynamic Pressure” created by air at a specific velocity. It turns out that 180 mph, the dynamic pressure is 1.17” Hg. This corresponds well with my ancient Mooney memories.

Doing the calculation for 80 mph the dynamic pressure is 0.23” Hg.

Go for looks.

Ed, you are right, @ 80MPH the numbers do show.23 in Hg, which means Bill is right with .11 psi.
@ 100MPH =.35in Hg =.17PSI
@ 120MPH = .51 in Hg =.24PSI
@ 60MMPH =.13 in Hg = .06PSI



2x18 scoop with 3" duct to the motor and a no loss calc show @ 80 MPH = 1+psi postive up to the filter. filter flow and subsequent pressure drop will show what pressure the TB will see. true numbers are slightly lower as I did not account for altitude.

JM

Jay, have you seen Bob Hertz car (http://www.britishv8.org/MG/BobHertz.htm)? I like what you're doing better so far -- wider seems to look more natural. But, thought Bob's might give you some ideas for finishing the front edge.

Rob

Rob, thanks, thais is nice, good craftsmanship, I see where it might be possible to split the Healy trim and widen it, that would be a nice touch

JM

".....Should be able to get the equivalent of a Moss supercharger by the time you get up to light speed....."

A simple calculation shows you only need 628 mph to get 7 psi (the pressure increases by the square of the velocity). However, I'm sure at that speed there are compressibility effects I'm not going to rack my brain over. I'm retired ;-)

.001 is better than the two zeros to the left of the # 1 Would you agree with that.

1) Ditto Carl's comment.

2) Saw a GT somewhere (I checked the BV8 gallery and couldn't find it - thought it might have been a race car) that had recessed scalloped (half-round) inlets at the front edge of the hood - maybe started 1" front the front edge and cut back about 5 - 6" and I think there was five of them (odd always looks better than even). Looked so good I thought it was factory :thumbup: - maybe somebody will know where I saw this car.

Looks good so far now fiber glass the sides to surve onto the hood and curve the front lip down and bondo, paint and volia more pissed off purists.
Just my 2 cents ( cdn)

Just a variation on the theme, I currently run a Edelbrock 500 on a performer manifold with only a 2" drop base filter for clearance reasons, was going to change to EFI as have most of the kit to do it including a Megasquirt MS2 V3 but since recalibrating the carb the engine runs so well I am a bit hesitant of doing the swap as it will take some time to get it right.

With the current filter being do inefficient and sucking in the very hot under bonnet air, I was thinking of using a small plenum on top of the carb with tubing to a couple of cone filters enclosed in boxes and feeding those from the brake ducts in the sebring valence with two 2-2 1/2" hoses fitted to the valence and feeding up through the inner wings.

The main intention is to create some space above the carb venturis and to feed the carb with much cooler air. I do have an MGRV8 hood so there is room direct above the carb to increase height.

Any thoughts,

Kevin.

Kevin, I used a cold air box on top of the carb with a hose to a cone filter. The balance is not a good place to locate the air cleaner. Low in the balance you will get lost of dirt and hot air from the pavement, many not in the UK.

Bill, With your air box above, why did you allow for such a small openning to the front, then a large filter behind. Would this setup not be drawing more air from the rear, from the engine bay.

The cone air filter has a 3" opening in the front. The air is also directed to the filter. Yes the rear is also a good location. I used this method because the air is force in to the box, from the cowling it would had to be drawn. Either way is good.
The openign is not small and the filter is large.
I no longer used that set up, I now have a supercharger so the air feed is different. The air filter is now inside the cowling in front of the radiator.

bill, thanks for the pic, pontiac has always been stylish to me.

progress

one more

Bill, that is a huge change. Those pipes must be double the diameter of the original image.

My first impression is "Ick", but "It is your bucket and you can carry coal in it", was my uncles favorite expression.

Good luck and don't ruin too many hoods in your endeavor.

BTW, do you need a couple of fiberglass doors to go with your front fenders?

Brad

Same size hose as the other 3"

McMaster-Carr woven wireless mesh would look great in there.

Bill - that orange hose looks just like the stuff I got form the UK for my FI TR7.

Danger Will Robinson!!

Those pictures oif what you have done with the bonnet make it at risk for being the winner in a Datsun 2000 lookalike contest!

That was my first reaction when I saw the latest picture. Not that there is anything wrong with that (he said, Channeling Seinfeld).